Automatic fire alarm



March 25, 1952 A. HIRSCHLE AUTOMATIC FIRE ALARM Filed April 4, 1950 INVEN TOR.

M?) c b 0 ll/red Patented Mar. 25, 1952 UNITED STATES PATENT OFFICEAUTOMATIC FIRE ALARM Alfred Hirschle, Philadelphia, Pa.

Application April 4, 1950, Serial No. 153,811

12 Claims.

The present invention deals with automatic fire alarms and is concernedprimarily with an alarm which is peculiarly adapted for installationwhere a concealed alarm is required.

At the present time there are many fire alarms which are installed aboutthe particular premises to be protected and which alarms areelectrically operated. Obviously should there be a power failure suchalarms are not effective. With this condition in mind, the presentinvention has in View as one of its more important objects the provisionof an automatic fire alarm which contains as a part of the alarm itself,a source of motive power for actuating the alarm. Thus, the operation ofthe alarm is not dependent on a current supply or other outside source.

While there have been proposed automatic fire alarms which are springactuated, such alarms are. ordinarily effective for only a short perioddue to the limitations of spring actuation. Thus, if the alarm is notheard during this short period its purpose will be defeated.

With this condition in mind, a further highly important object of theinvention is to pro-- vide an automatic fire alarm which includes asource of motive power which will be effective over a prolonged periodso as to provide a period of operation of sufiicient extent to affordreasonably definite assurance that the alarm will be heard once it isset off.

A further highly important object of the invention is to provide anautomatic fire alarm that is peculiarly adapted to be concealed invarious home appliances, such as lamp bases, ceiling. light fixtures,ornamental door chime covers, and comparable places, and also forinstallation as auxiliary equipment for electrically operated alarmsystems.

In carrying out the above noted objects, the automatic fire alarm ofthis invention avails of the principles of jet propulsion in providingthe source of motive power. A rotor is provided in the form of an8-shaped container of compressed gas and one end of this container takesthe form of a frangible glass vial which when broken will release thegas and cause the rotor to rotate for a prolonged period. As a practicalmatter it has been found that these rotors may be designed to continuein operation for a period ranging from three to four minutes.

Another somewhat more detailed object of the invention is to provide, inan automatic fire alarm of the character indicated, a rotor whichincludes as an essential element a clapper in the form of a spring armtogether with a fusible link for normally retaining the clapper in aretracted sprung position. This clapper is so positioned relative to thevial at the end of the gas container that when it is released by meltingof the fusible link it will first strike the glass vial and break it tocause release of the gas and thereby start the rotor into rotation. Theend of the clapper engages tabs or tangs which are formed on anenclosing bell to sound the alarm.

Various other more detailed objects and ad vantages of the inventionsuch as arise in con nection with carrying out the above noted ideas ina practical embodiment will, in part become apparent, and in part behereinafter stated as the description of the invention proceeds.

The invention, therefore, comprises an automatic fire alarm whichconsists essentially of a rotor that includes an S-shaped container forcompressed gas having a frangible vial at one end and a clapper which isnormally maintained in a retracted sprung position by a fusible link butwhich when released will fracture the vial and release the gas from thecontainer to cause rotation of the rotor. A bell is disposed about thisrotor and carries inwardly extending tabs which are struck by theclapper as the rotor rotates to cause the sounding of the alarm.

For a full and more complete understanding of the invention, referencemay be had to the following description and accompanying drawingwherein:

Figure 1 is a top plan view with parts broken away and shown in sectionof an automatic fire alarm designed in accordance with the precepts ofthis invention; and

Figure 2 is a side view partially in section and partially in elevationof the alarm shown in Figure 1.

Referring now to the drawing wherein like reference characters denotecorresponding parts, the automatic fire alarm of this invention is shownas being housed in a casing which is referred to in its entirety by thereference character C. The casing C comprises a bottom l0 having adownwardly extending peripheral flange H in the form of a bead whichreceives the lower edge of a cylindrical wall l2. The cylindrical walll2 merges in with a top wall l3 that is integrally joined thereto.

Supported from the top wall l3 of the casing C is a bell which isidentified in its entirety by the reference character B. The bell Bcomprises a top wall l4 having a central offset portion I5 which issecured to the top wall I3 of the casing C as by the rivet shown at l6.Integrally joined to this top wall I3 of the bell B is a cylindricalwall I! which it is noted is spaced from the wall l2 of the casing.Extending inwardly from this cylindrical wall I! at appropriately spacedintervals are a plurality of tabs i8 which preferably are struck fromthe bell and integrally connected thereto.

A rotor is referred to in its entirety by the reference character R. Itincludes a bracket [9 that is pivotally mounted as by a pivot pin 20 andbushing 2| on the bottom H) of the casing. This bracket includes a pairof spring arms 22 and 23 which partially encompass and securely grip agas container 24. The latter is of the S-shape depicted in Figure 1 andmay be made of any appropriate material, although the invention hasparticularly in mind the use of glass because of its frangiblecharacteristics.

The container 24 is filled with gas under a required pressure and issealed off at one end by the vial shown at 25. The vial25 is weakened atanappropriate point, preferably by the etchingshown at 26 so that whenit is struckby the clapper about to be described, it will break off at 2this-- point.

1 Formed as a part of the bracket l9 and integrally connected to thespring arm 23 is a clapper 21 which is formed with a ball 28 at its freeend. This clapper is of exactly the proper lengthto cause the ball 28 tostrike the tabs [8 when the rotor R rotates with the clapper in areleased position.

'Normally detaining the clapper 21 in a retracted sprung position is afusible loop 29. Thi: loop 29 encircles both the container 24 and thclapper'2l so as to hold the latter in the position illustrated inFigure 1. The loop 29 is made -from an appropriate material which willfuse at a certain predetermined temperature. Thus, ii the alarm isintended to be set off at one hundred thirty degrees Fahrenheit thefusible link 29 must be made of a material which will melt at onehundred thirty degrees Fahrenheit. Fusible U materials of this natureare well known and available to the public as such.

Operation One or more of the fire alarms above described willbe locatedat appropriate places in the particular premises to be protected. If afire should start the moment the temperature at the location of any ofthese alarms reaches the melting point of the fusible loop 29, this linkwill fuse and release the clapper 21. The first thing this clapper doesis to spring over into the broken line position of Figure 1 in which itengages the frangible vial 25 and breaks the latter off at the marking26. The gas which is compressed in the container 24 is now releasedthrough the restricted opening provided by the vial and due to reactiontherotor R begins to rotate under the now well accepted principles ofjet propulsion. As the rotor B so rotates, the ball 28 at the endof theclapper 21 strikes the tabs 18 on the bell and causes the alarm tosound. Due to the springy nature of the clapper arm 21 the engagement ofthe ball with the tabs l8 offers but little resistance to this rotation.With the gas in the container 24 under a proper degree of compression,the rotor will rotate for a period ranging from three to four minutes.

After an alarm has once been sounded it is obvious that a container 24may be replaced by a new one that is suitably charged with thecompressed gas.

While a preferred specific embodiment of the invention is hereinbeforeset forth, it is to be clearly understood that the invention is not tobe limited to the exact materials, constructions, and mechanismsillustrated and described because various modifications of these detailsmay be provided in putting the invention into practice within thepurview of the appended claims.

What is claimed is:

1. In an automatic fire alarm, the combination of: a bell having a wallfrom which projects a tab, a pivotally mounted rotor including a clapperadapted to engage said tab to sound the bell, a container for gas underpressure included as a part. of said rotor for causing rotation thereof,and means releasing said gas from said container causing rotation ofsaid rotor.

2. In an automatic fire alarm, the combination of: a bell having a wallfrom which projects a tab, a pivotally mounted rotor including a clapperadapted to engage said tab to sound the bell, a container for gas underpressure included as a part of said rotor for causing rotation thereof,said container being formed with a frangible glass vial at one end whichwhen broken releases gas from the container to initiate rotationthereof, and means for breaking said glass vial to release said gas fromsaid container causing rotation of said rotor.

3. In an automatic fire alarm, the combination of: a bell having a wallfrom which projects a tab, a pivotally mounted rotor including a clapperadapted to engage said tab to sound the bell, a container for gas underpressure included as a part of said rotor for causing rotation thereof,said container being formed with a frangible glass vial at one end whichwhen broken releases gas from the container to initiate rotationthereof, and fusible means normally maintaining said clapper in aretracted sprung position with the glass vial positioned to be engagedby said clapper upon release thereof from said fusible means.

4. In an automatic fire alarm, av casing, a bell carried by said casingand including a circular wall from which extend inwardly a plurality oftabs, a rotor pivotally mounted in said casing, a clapper included as apart of said rotor and comprising a spring arm with a ball at the freeend thereof adapted to strike against said tabs, an S-shaped containerof=gas included as a part of said rotorand having a'frangible vial atone end, said vial being positioned to be engaged and fractured by saidclapper when the latter is released, and a fusible loop normallyencircling said clapper arm and said container to maintain said clapperin a retracted position.

5. In an automatic fire alarm, a casing, a bell carried by saidcasing-andincluding a circular wall from which extend inwardly aplurality of tabs, a bracket pivotally mounted centrally of said casingand including a pair of upwardly extending spring arms, ans-shapedcontainer of gas grippingly engaged by said spring arms to be removablyheld thereby, a clapper arm extending outwardly from one of said springarms and having a ball at its free end adapted to engage said tabs, anda fusible loop normally encircling a portion of said container and saidarm to maintain said clapper in a retracted sprung position, saidclapper being released upon the melting of said loop and adapted tobreak said containerto release said gas and cause movement of saidcontainer whereby said clapper is caused to be moved so as to engagesaid tabs and sound an alarm.

6. In an automatic fire alarm, a casing, a bell carried by said casingand including a circular wall from which extend inwardly a pluralit; oftabs, a bracket pivotally mounted centrally of said casing and includinga pair of upwardly extending spring arms, an S-shaped container of gasgrippingly engaged by said spring arms to be removably held thereby, aclapper arm extending outwardly from one of said spring arms and havinga ball at its free end adapted to engage said tabs, and a fusible loopnormally encircling a portion of said container in said arm to maintainsaid clapper in a retracted sprung position, said container being formedwith a frangible vial at one end which is positioned to be engaged bysaid clapper upon release thereof to be fractured thereby.

7. In an automatic fire alarm, an alarm element and a container of gasadapted to be actuated by release of the gas to sound said alarmelement.

8. In an automatic fire alarm, an alarm element, a rotor including acontainer of gas that is adapted to be rotated upon release of gas fromsaid container, and means for causing rotation of said rotor to rendersaid alarm element effective.

9. In an automatic fire alarm, a rotor cartridge comprising an S-shapedcontainer of gas having a frangible vial at one end.

10. In an automatic fire alarm, a rotor cartridge comprising an s-shapedcontainer of gas having a frangible vial at one end, said vial beingformed with an etched mark whereby said vial will be fractured at saidmark.

11. A fire alarm comprising a bell, a container containing gas underpressure movably supported adjacent said bell, a clapper secured to saidcontainer, and means releasing said gas from said container causingmovement of said container and said clapper whereby said clapper iscaused to strike said bell and sound an alarm.

12. A fire alarm comprising a bell, a container containing gas underpressure movably supported adjacent said bell, a clapper secured to saidcontainer, and means responsive to temperature releasing said gas fromsaid container causing movement of said container and said clapperwhereby said clapper is caused to strike said bell and sound an alarm.

ALFRED HIRSCHLE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,047,706 Roberts et al Dec. 17,1912 2,506,983 Williams u May 9, 1950

